Stripped oil drain plug thread, thoughts on oversize plugs

[expat2000]

Hi all

First start up after winter of my 85 GSX750ES cafe racer. Started on the button after sitting for 5 months in a sub zero garage in Norway (down to -20 some nights).

Ran it for 20 minutes to warm it up for an oil change, drained it, changed filter, all good.

Spinning in the drain plug, by hand, and it goes a bit tight then loose....backed it out and the threads come with it. Looks like its gone previously and been helicoiled. 

ARSE!

So options seem to be oversize plug or new sump, quite a price difference as I can get the oversize plug for £20 locally (with tap) or wait a couple of weeks for a replacement sump from the UK (£50 price, plus £20 postage plus £20 import duty).

So has anyone gone down the oversize plug route, recommended or not?

Also I'm assuming I can take the sump plate off without removing the engine from the frame? Just a case of getting the exhaust off first?

Cheers. 

[wraith]

@imago has found so nice replacement inserts 

[Gixer1460]

I would have thought a helicoil is a bad solution for a through hole as this, difficult to lock into place - as you've found out! I'd go for oversize plug for cheapness but deffo take sump off for accurate job!

[TonyGee]

1 hour ago, Gixer1460 said:

I would have thought a helicoil is a bad solution for a through hole as this, difficult to lock into place - as you've found out! I'd go for oversize plug for cheapness but deffo take sump off for accurate job!

what about a short timesert ?  if its short enough it should lock in place and with the aid of some locktite. 

[Suzukian]

The Heli-Coils I use have serrated back edges which hold the inserts into place.  Maybe they are different or are different kinds?  How about one of those rubber plugs that expand, and if you hit a bump, piss your oil out, make your back tire slip, and kill your engine, or, in a best case scenario, work as advertised.  

 

 

[rodneya]

My Kat had an oversized plug when I got it, but it was some sort of pipe thread and what looked like a hydraulic fitting. I replaced it with a Mishimoto M18 magnetic drain plug (already had the Tap). Its pretty big, but  works great.

[TonyGee]

44 minutes ago, Suzukian said:

The Heli-Coils I use have serrated back edges which hold the inserts into place.  Maybe they are different or are different kinds?  How about one of those rubber plugs that expand, and if you hit a bump, piss your oil out, make your back tire slip, and kill your engine, or, in a best case scenario, work as advertised.  

 

 

is that a new type of butt plug !!!!  

[Suzukian]

Hah!  I wouldn't want to be the one to pull the lever!

[Suzukian]

If you use "Alum-Alloy, with the bolt in place, it will fork around the threads, and you will be able to unbolt it, and have newly formed threads.  Since the bolt will be very hot, you have to wait till everything cools down.  I have fixed a lot of aircraft parts with this stuff, cylinder heads, all manner of things.  It's strength is incredible, it can be milled..

 

https://www.alumiweld.com/

 

 

Edited April 2, 2023 by Suzukian

[imago]

11 hours ago, wraith said:

@imago has found so nice replacement inserts 

TimeSert. They're a permanent 'repair' unlike HeliCoil which are a cheap fix. HeliCoil are the engineering equivalent of Scotch locks.

TimeSert requires the hole to be drilled out, tapped and have a counterbore. When the insert is fitted the tool rolls the tube out to a larger diameter at the end of the threads which stops it backing out if the bung or stud sticks or corrodes.

The only reason they're not as widely used as HeliCoil is that they cost more, but it's very much a case of 'buy cheap, buy twice'.

[expat2000]

Ok, thanks for all the advice. I'd discounted helicoils already as getting the holed drilled and finding a helicoil that size and then its a bit of a bodge really. Safer to just get a replacement sump. I did look at Timeserts but again the cost and time factor and difficultly in drilling it at home ruled that out vs getting another sump. 

Pulled the sump off this morning, and about half the threads were just gone. Previous helicoil repair was in multiple pieces.

Found this at my local motor factors place, its actually designed to be used without a drill, you just run the tap down the existing hole. Goes from M14x1.25 to M15x1.5 thread. Not much of an increase so plenty of metal around the hole still. (Not sure why it comes with 6 drain plugs) Thought its worth a punt for £20, worst case I scrap the sump pan and have to buy another one, which is where I was anyway.

I have to say for a cheap and fast fix it woked remarkably well. Slow and steady with tap using a T-bar and 11mm socket (?) and the new thread looked good. New drain plug with copper washer, correctly torqued up without drama.

All back together now and seems to be oil tight after running it up to temperature.

Just need the snow to melt now and I can get out on the road.   

[imago]

2 minutes ago, expat2000 said:

Ok, thanks for all the advice. I'd discounted helicoils already as getting the holed drilled and finding a helicoil that size and then its a bit of a bodge really. Safer to just get a replacement sump. I did look at Timeserts but again the cost and time factor and difficultly in drilling it at home ruled that out vs getting another sump. 

Pulled the sump off this morning, and about half the threads were just gone. Previous helicoil repair was in multiple pieces.

Found this at my local motor factors place, its actually designed to be used without a drill, you just run the tap down the existing hole. Goes from M14x1.25 to M15x1.5 thread. Not much of an increase so plenty of metal around the hole still. (Not sure why it comes with 6 drain plugs) Thought its worth a punt for £20, worst case I scrap the sump pan and have to buy another one, which is where I was anyway.

I have to say for a cheap and fast fix it woked remarkably well. Slow and steady with tap using a T-bar and 11mm socket (?) and the new thread looked good. New drain plug with copper washer, correctly torqued up without drama.

All back together now and seems to be oil tight after running it up to temperature.

Just need the snow to melt now and I can get out on the road.   

 

That'll be fine as long as you don't go 'full shaved monkey' when you're tightening the bung up. 

[expat2000]

4 minutes ago, imago said:

That'll be fine as long as you don't go 'full shaved monkey' when you're tightening the bung up. 

I learned a long time ago that any time you screw something into these engines the torque wrench is a must!

 

[Suzukian]

Maybe copy cat Heli-Coils aren't any good, the the Original ones are not crap by any means.  I have found that most people who say that don't insert them correctly, use the wrong size drills, and don't use the proper tap that comes with the "FULL" Heli-Coil" kit.  Why would the stud affect the coil if it is stainless steel?  I don't know what "Scotch locks" are, never heard of that, but I'm in the U.S., that may be a U.K. thang.  I've never had a Heli-Coil fail me, and they can take more torque than the aluminum threads they replace can.

[bitzz]

Threaded inserts get a bad name. Installed correctly they work well. They were not designed for thread repair, that was an after thought, they were designed for the aerospace industry to use to make aluminum connections stronger. The inside thread is steel so it doesn't pull out as easy, and the insert increases the size of the fastener, making the connection stronger, more surface area in the connection interface.

The people that tell me that helicoil are crap are the people that just ham fisted or galled the thread out of their oil pan or spark plug, where my aerospace machinist friends swear by them.

[rodneya]

18 minutes ago, bitzz said:

Threaded inserts get a bad name. Installed correctly they work well. They were not designed for thread repair, that was an after thought, they were designed for the aerospace industry to use to make aluminum connections stronger. The inside thread is steel so it doesn't pull out as easy, and the insert increases the size of the fastener, making the connection stronger, more surface area in the connection interface.

The people that tell me that helicoil are crap are the people that just ham fisted or galled the thread out of their oil pan or spark plug, where my aerospace machinist friends swear by them.

[coombehouse]

On my katana, I went with an oversized plug, m16 I think common to fords, BMW minis etc. There's nothing wrong with helicoils at all but in this application, there isn't really enough depth of material to hold the insert in place reliably. 

[imago]

9 hours ago, bitzz said:

Threaded inserts get a bad name. Installed correctly they work well. They were not designed for thread repair, that was an after thought, they were designed for the aerospace industry to use to make aluminum connections stronger. The inside thread is steel so it doesn't pull out as easy, and the insert increases the size of the fastener, making the connection stronger, more surface area in the connection interface.

The people that tell me that helicoil are crap are the people that just ham fisted or galled the thread out of their oil pan or spark plug, where my aerospace machinist friends swear by them.

Quite right, if you want to build an aeroplane then fitting helicoil or similar from new as part of the manufacturing process to strengthen mechanical connections is the way to go. You're also correct that helicoil weren't designed for thread repair.

Thing is, this is a thread about a thread repair on a forum for Suzuki motorcycles. Which is why using a thread insert which was designed for repair rather than manufacture, to a part which will have frequent removal and replacement, timesert is more suitable.

The people that tell me helicoil are suitable for all applications just don't understand selecting the correct part and method for repair.

[imago]

11 hours ago, Suzukian said:

Why would the stud affect the coil if it is stainless steel?  

Galvanic corrosion.

[Gixer1460]

49 minutes ago, imago said:

Galvanic corrosion.

Possible but Highly unlikely especially as the bond is surrounded by aluminium (a more sacrificial element) For it to occur there needs the presence of a decent conductive liquid - sea water / salt water - is usually quoted but a SS thread in a block in contact with both Aluminium and steel will be sealed (pretty much) from any contact with water / oil / anything via the gaskets Plus a coating of thread locker will also isolate contact to virtually zero - maybe give it a hundred years or so and you might lose 1% of the material - probably best not worry about it?

[imago]

13 minutes ago, Gixer1460 said:

Possible but Highly unlikely especially as the bond is surrounded by aluminium (a more sacrificial element) For it to occur there needs the presence of a decent conductive liquid - sea water / salt water - is usually quoted but a SS thread in a block in contact with both Aluminium and steel will be sealed (pretty much) from any contact with water / oil / anything via the gaskets Plus a coating of thread locker will also isolate contact to virtually zero - maybe give it a hundred years or so and you might lose 1% of the material - probably best not worry about it?

All true enough, but given that we're talking about a sump bung which is in a thin alloy section with heat/cool cycles and exposed to road snot/salt (and you wouldn't be using threadlock on a sump bung). Why add the extra complication if you don't have to? Time Serts are carbon steel, so the only issue with binding/corrosion is between the insert and the sump where instead of being a problem it actually adds to the fix.

It's horses for courses, but in most repair situations for a damaged thread in aluminium/alloys a Time Sert is better suited than a stainless coil.

[Gixer1460]

Sorry I was reacting to the included word 'stud' ? Maybe wrong terminology used? I'm still confused about the 'Actual' risk of GC and in particular this case! As said a conductive liquid is required to get to the threads, which seeing as they are more likely to be oily (a natural insulator) and all designed to keep oil in and water out the risk is extremely low IMO. Afterall aluminium sump and steel bung rarely corrode sufficiently to fail? I honestly don't have issues with Helicoils or Timeserts - used in suitable locations - and a M14 Timesert isn't cheap solution if you have to buy the whole kit for one thread! Hence why I would go oversize ie M14 - M16 as there should be enough metal to take it (deffo if it could take a Timesert!) and stress on threads would be less with bigger thread at required torque . . . . & its cheaper LOL!

[imago]

12 minutes ago, Gixer1460 said:

Sorry I was reacting to the included word 'stud' ? Maybe wrong terminology used? I'm still confused about the 'Actual' risk of GC and in particular this case! As said a conductive liquid is required to get to the threads, which seeing as they are more likely to be oily (a natural insulator) and all designed to keep oil in and water out the risk is extremely low IMO. Afterall aluminium sump and steel bung rarely corrode sufficiently to fail? I honestly don't have issues with Helicoils or Timeserts - used in suitable locations - and a M14 Timesert isn't cheap solution if you have to buy the whole kit for one thread! Hence why I would go oversize ie M14 - M16 as there should be enough metal to take it (deffo if it could take a Timesert!) and stress on threads would be less with bigger thread at required torque . . . . & its cheaper LOL!

I was just responding to an earlier question about stainless not corroding or how it could. It all gets a bit muddled on threads, especially when it starts to drift away from what the OP was asking.

Going way back up @wraithmentioned that I use other inserts, I answered with what and why as I use Time Serts (for the business as well as my bikes). TimeSerts are expensive no doubt, and for a one off probably too expensive. I think the M14 inserts on their own are about £15:00. If a customer needs one fitted to a sump it's a £50:00 job with the sump already removed which is pricey but if you can't get a sump and want a permanent repair then that's all I use as I don't get any come backs.

Aside from customer's stuff and my bikes it makes no difference to me if people use PlayDough, bang in a bit of broom handle or TIG weld a hydraulic fitting in. 

[Gixer1460]

Quote

TIG weld a hydraulic fitting in. 

Now there's a thought - permanent fitted tap / valve 

[imago]

5 minutes ago, Gixer1460 said:

Now there's a thought - permanent fitted tap / valve 

Not with my TIG welding!